Electron discharge device



A. W. HULL April 26, 1932.

ELECTRON DISCHARGE DEVICE Original Filed Aug. 19, 1927 Fig l.

mfw m m m t t m. A e 1 .5 m H H ID ent application is Patented Apr. 26,1932 UNITED STATES ALBERT W. HULL, F SCHENECTADY, NEW YOBK ASSIGNOR 1'0GENERAL ELECTRIC PATENT" OFFICE COMPANY, A CORPORATION OF NEW YORKELECTRON DISCHARGE DEVICE Application filed August 19, 1927, Serial No.214,198. Renewed February 17, 1982.

The discharge devices of the four-electrode type. In my copendinapplication, Serial N 0. 696,665, filed Marc 3, 1924, of which the presacontinuation in part, I have disclosed an arrangement in which ascreening grid interposed between an anode and a control grid andextending slightly beyond the control grid and anode serves to interceptelectrostatic lines of force extending beyond the ends of theseelectrodes. Al-

1 anode to a minimum, I have found that the diameter of the shieldingsame result may be produced by the use of a thin metal washer mountedadjacent one end of the screening grid, the inner diameter of the washerbeing slightly greater than the grid and the outer diameter of thewasher being substantially equal to the inner diameter of the receptaclein which the electrodes are mounted.

The novel features which I believe to be h characteristic of myinvention are set forth to with particularity in the appended claims.The invention itself, however, will bestbe understood from reference tothe following specification when considered in connection with theaccompanying drawings in which Fig. 1 shows an elevation partly brokenaway of an electron discharge device constructed in accordance with thepresent invention; Fig. 2 is a perspective view on an enlarged scale ofthe upper end portion of the electrode structure shown in Fig. 1; whileFig. 3 indicates a modified form of shielding grid.

I have indicated in Fig. 1 an evacuated receptacle 1 in which aremounted a V shaped filamentary cathode 2, a control grid 3, an anode 4and a screening grid 5 interposed between the control grid and anode.Current for the cathode2 is supplied by leading-in conductors 6 and 7which extend through stem 8. The end of cathode 2 remote from the stemis supported by a spring 9 secured to the end of a supporting rod 10.The opposite end of rod 10 is embedded in a block 11 of insulatingmaterial. Block 11 is supported by rods 12 and 13, the opposite ends ofwhich present invention relates to electron though such an arrangementis effective in are embedded in stem 8. Screening at its lower end, isprovided with a ring 15 secured to the grid supporting wires 14. Ring 15is provided with a lateral extension secured to rod 13. Rods 12 and 13are provided at a point adjacent stem 8 with a flat rectangular metalbrace 16 having a central gpening, not shown, to accommodate the leadsor tends through stem 8 and forms a continuation of the leading-inconductor 17 by which current is supplied to the screening rid. Supports18 and 19 of the control gri are also embedded in support 19 isconnected to the leading-in conductor 20 whereby current is supplied tothe control grid. Anode 4 is supported from stem 8 by supports 21 and 22and support 21 grid 5,

theinsulating block 11 and is connected to leading-in conductor 23 whichsupplies current to the anode. The screening grid extends an appreciabledistance beyond the lower ends of the control grid and anode. A thinannular metal aving an outer diameter substantially equal the diameterof receptacle 1 and an inner diameter slightly larger than thediameterof the screening grid is mounted on rods 12 and 13 adjacent the end ofthe screening grid and secured to the grid supporting rods 14. Thecontrol grid lead 20 is brou ht out of receptacle l at the opposite endFrom the anode lead so that there is no unscreened capacity between thetwo leads.

It will be apparent that the disc 24 is effectively interposed betweenthe end of the anode and the lead to the control grid and thus serves tointercept any electrostatic lines of 1force extending from the anodetoward that ea-d.

In the arrangement shown in Fig. 3, I employ a modified form ofscreening grid construction in which the screening grid is made up ofannular metal discs 27 threaded on rods 25 and 26. At the upper end ofthe screening grid, an annular metal shield -or disc 24, similar to thatdisclosed in Figs. 1 and 2, is mounted. A similar disc may be providedat the opposite end of the screening grid if desired.

The potential applied to the screening grid member or washer 24 forproducing screening action is preferably a constant potential so chosenthat it has no deleterious effect upon the usual 0 ration of thedischarge device. This potential is preferably fixed at a value which ismore positive with respect to the cathode than the potential of thecontrol grid at any time. With the arrangement disclosed the capacityefiect between the control grid and the anode is substantiallyeliminated, the arrangement of the metal shield serving to intercept notonly the direct electrostatic lines of force extending between thecontrol grid and anode but also electrostatic lines extending in curvedpaths between the two electrodes as well as the electrostatic linesextend ng from the anode to the lead for the control grid or from theanode lead to the lead from the control grid. Although I have indicatedthe screening grid as extending slightly beyond the upper end of anode4, such an arrangement is not essential. Grid 5 might be so disposedwithin anode 4 that it would not extend beyond the upper end of theanode. The shield 24 should of course be spaced a slight distance fromthe anode. Th s might be accomplished by extending the supporting wiresof the shielding grid a slight distance beyond the end of the anode.

What I claim as new'and desire to secure by Letters Patent of the UnitedStates is:

1. An electron discharge device comprising a receptacle, a plurality ofelectrodes mounted therein, said electrodes comprising a cathode, anodeand control grid, and a screening grid interposed between the anode andcontrol grid and adapted to eliminate the oou ling eifect between thelast mentioned e ectrodes, said screenin grid being provided at one endthereof wit a substantially flat annular conducting shielding memr. 2.An electron discharge device comprising a container, a plurality ofelectrodes mounted therein, said electrodes comprising an electronemitting cathode, an anode and a control grid, and means for eliminatingthe coupling effect of capacity between the control grid and anode, saidmeans comprising a screenin grid provided with a flat metal shieldingdisc ad acent one end thereof and interposed between the end of theanode and a lead connected to the control grid.

3. An electron discharge device comprising a receptacle, a plurality ofelectrodes mounted therein, said electrodes comprising a cathode, anodeand control grid, and a screen ing grid interposed between the anode andcontrol grid, said screening grid having an annular conducting shieldingmember mounted adjacent one end thereof and electrically connectedthereto, said member having an outer diameter substantially equal to theinner diameter of the receptacle.

4. An electron discharge device comprising a receptacle, an electronemitting cathode, I

an anode and a control grid mounted in the receptacle, a screenin gridinterposed between the anode and t e control grid and insulated from thecontrol grid, and a connection at one end of the screening gridcomprising a metal washer having an outer diameter substantially equalto the inner diameter of the receptacle and an inner diametersubstantially equal to the diameter of the screening grid.

5. An electron discharge device compris ing a container, a plurality ofelectrodes mounted therein, said electrodes comprising an anode and acontrol grid, the conductors of which pass through opposite ends of thecontainer and means for eliminating the effect of capacity couplingbetween the control grid and the anode, said means comprising ascreening rid and a metallic member adjacent the end of said electrodesfrom which the grid conductor is taken.

6. An electron discharge device comprising a container, a plurality ofelectrodes concentrically mounted thereln, said electrodes comprising ananode and a control'grid, means for eliminating the effect of capacitycoupling between the control grid and anode, said means comprising ascreening grid interposed between the anode and control grid andprovided with a metallic member extending in a plane transverse to theprincipal axis of the electrodes and electrically connected to saidscreening grid and interposed between the end of the anode and a leadconnected to the control grid.

7. An electron discharge device comprising a container, a plurality ofelectrodes concentrically mounted therein, said electrodes comprising ananode and a control grid, means for eliminating the effect of capacitycoupling between the control grid and anode, said means comprising ascreening grid interposed between the anode and control grid andprovided with a metallic member extending in a plane transverse to theprincipal axis of the electrodes and having an area greater than thetransverse cross-sectional area of the anode said member beinginterposed between the end of the anode and a lead connected to thecontrol grid.

8. An electron discharge device comprising a container, a plurality ofcylindrical electrodes concentrically mounted therein, said electrodescomprising an anode and a control grid, means for eliminating the efiectof capacity coupling between the control grid and the anode, said meanscomprising a metal washer having an outer diameter substantially equalto the inner diameter of the container and an inner diameter relativellarger than the diameter of the control grid In witness whereof I havehereunto set my hand this 17th day of Au st, 1927.

ALBER W. HULL.

" Patent No. 1,855,886.

ALBERT w. HULL.

Granted April 26, 1932, m

It is hereby certified that error appesrs in the pi'intedspecification'of the above numbered patent-requiring correction asfollows: Page 2, line 59,'claim 3,- after the'ivord "grid". firstoccurrence, insert the words and comma and adapted to eliminate thecoupling effect between the East mentioned electrodes,; and that'thesaid Letters Patent should be read with this correction therein'that thesame may conform to therecord of the ease in the Patent Office.

Signed and sealed this 21st day of June, A. D. 1932.

M. J. Moore,

( v Acting Qomm'issioner of Patents.

, CERTIFICATE or CORRECTION;

Patent No. 1,855,886.," 4 f t Granted April 26, 1932; to

1. 5 ALBERT W HULL.

It is hereby certified that error a pp'ears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,line 59, claim 7 3, after the word "grid" first .occiirrence, insert thewords and command adapted to eliminate thecoupling effect between thelast mentioned-electrodes,;

and that the said Letters Patent should be read'with this correctiontherei n that the same may conform to the record of-the case in thePatent Office.-

Signed and sealed this 2lst'day of June, A. D; 1932, r

, M. J. Moore,

(Seal) Q Acting Commissioner of Patents.

